Brake construction



Nav. 24,1925. f 1,562,823

` A. Y. DODGE BRAKE CONSTRUCTION Filed March 29, 1924 of the pedal to cause a slower,

Patented Nov. 24, 1925.

UNITED STATES A. PATENT 'oFFIc-E.

ADIEL Y. DODGE, OF SOUTH BEND, INDIANA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO BENDIX BRAKE COMPANY, 0F CHICAGO,7 ILLINOIS, A CORPORATION OF ILLI- NOIS.

BRAKE COSTSTRUCTION.

Appncation mea March 29, 1924. seria; No. 702,768.

To all whom t may concerne.' A v Be it known that I, ADIEL Y. Dononfa South Bend, in the county 'of St. Joseph and State of Indiana, have ,invented new and useful Improvements in 'Brake Construction, of which the following is a full, clear, concise, and exact description, .reference being had to the accompanyin drawing, forming a part of this speci cation.

My invention relates'to automobile brake construction.

One of the objects of my invention is to provide an automobile brake construction in which the movement ratio of the reach rod with respect to the pedal decreases as the pedal movement progresses. struction is desirable in order that a short initial movement of the brake pedal will take up most of the slack in the brake mechanism and enable the succeeding movement more powerful action of the brake. This construction is designed to be used in place of the expensive and intricate Servo devices now in use in foreign automobile practice. It has been found in practice that 5 or 6 inches of pedal movement is all that is desirable in passenger automobiles. Withheavy cars and cars equipped with four wheel brakes it is desirable to use as much as possible of this pedal travel for useful work. All brakes must have clearance and all brake mechanism will have some play and give. It is an object of my invention to take up practically all of this slack with a Th minimum of pedal movement. It is a further object of my invention to provide a device which will take up the slack with a minimum of pedal movement, and thereafter applying a powerful substantially uniform effort on the brake rod through the balance of the pedal movement.

Further objects will appear from the description and claims.

In the drawings in which an embodiment of my invention is shown- Figure 1 is a diagrammatic -side elevational view showing the brake pedal, the brakeand the transmission from the pedal to the brake;

r Fig. .2 is a side elevational view showing a Such a con-v difierent form of connection between the pedal and reach rod;l citizen of the United States, residing at Fig. 3 is a sidevelevational view showing still another form of connection; and

Fig. 4 is an enlarged sectional view showing one of the actuating devices used in the imperforate fluid pressure transmission system.

The mechanism for controlling the movement ratio of the reach rod with respect to the pedal in all of the forms shown is carried by the pedal itself and acts between the pedal and a reach rod forming partof the transmissionl to the brake.

Referring first to the construction shown in Fig. 1, this comprises a brake pedal 10,

pivotally mounted at 11, a brake 12, an imperforate hydraulic transmlssion 13, and\a movement ratio controlling device 14, between the pedal 10, and the reach rod 15,

connected with the hydraulic actuator 16.

Thevimperforate hydraulic system shown comprises the compressible and expandible actuator 16 (Figs. 1 and 4), and expansible and compressible actuator 17, similar to the actuator 16, for. acting on the brake shoes 18 and 19, and a tube 20, affording com-` munication vbetween the actuator 16 and the actuator 17.

The movement ratio controlling device 14 in Fig. 1 comprises a lever 21 having a follower portion 22, a cam portion23 formed on the pedal 10, and a link '24 pivotally connected at 25 with the lever 21 and pivotally connected at 26 e camlever 21 is 27 with the reach rod 15 whlch 'acts on the hydraulic actuator 16. A study of the movement ratio controlling device will show that the initial pedal movement will cause a relawith the foot pedal.l pivotally connected at tively great movement of the reach rod 15 due to the abrupt rise in the cam portion By suitable design of the' cam portion 23 any desired movement ratio of the reach much slower movement substantially concentric I.

4 secure The reach rod will travel in a straight of the hydraulic actuator. As herel shown,

`line due toits connection with the actuator 16. I y

Fig. 4 shows, in detail, one construction it comprises an integral corrugated metal chamber or cell 28, having a plurality of deep annular corrugations 29 which enable Ythe cell to be readily expanded and comressed to vary its capacity to cause the flow of the fluid in one direction or the other through the tube-20. As the system isimerforate, having no movino` parts extending through openings from the insideto the outside of thesystem, there is no chance' for leakage.

Fig. be used with the- 'ordinary mechanical 'transmission if desired.- In this `form the movement ratio controlling construction between the pedal 30and the'reach rod 31 comprises a leverp32, pivotally connected at 33, with the reach rod, a link 34, pivotally v connected at with the lever 32 and pivotally connected at 36 with rthe pedal 30 and a second link v37, pivotally connecte at 38 with the lever '32 and ivotally connected at 39 with the extension 40 of the pedal. In this construction' also, a plot of. the movement of the edal and the parts of the movement ratio o the /neach rod 31 with res ct to the pedal 30 decreases as the Pe e struction the link 34 will remain substan- 1 tially horizontal iiik its movement, due to the d zontal.`

- that the movement controllin 44, engagmg direction of the 'forces actin on it.,y If desired additionalvv means may` insurethat it does remain substantially hori- The points indicated at 1, 2,3, 4f'and 5 show the different positions which the piv otal point 33 of the reach rod will occupy correspondin tothe points 1, 2*, 3, 4, and 5 of the pe al movement. It willbe seen ratio of the reach rod with res ect to the pedal decreases materiallyv ast e pedal movement progresses. ig.3 shows still another form of .move- 1d l ment ratio'controlling construction which may be used with the ordinary mechanical brakey transmission if desired. This form is similar to the construction shown in Fig.

1, except 'that the reach rod 41, in Fig. 3

is movedin the opposite direction to that.

of Fig. 1. In this the movement ratio orm, construction comprises a lever 42, pivota y` connected at 43 with the reach rod 41, and 'having a cam followerd or roller the cam portion- 45 ofthe pedal, and a link 46 pivotally connected at 47 with the lever 42, and pivotally connected at 48 with the pedal 49. In this form, the initial movement of the pedal 49 will cause and 2 shows a construction which may |to a considerable lower ratio,

al movement progresses. this conprovided to A, :,Bcaeas a relatively great movement of the reach rod 41 due to the abrupt rise of the cam portion 45, and the succeeding movement of the reach rod will be comparatively slow` p owerful, as the succeeding cam portion may concentricA withv the axis'of the kpedal 49 so that this succeeding movement of the reach rod is due only -to the action'of the link 46. In the construction shown in Fi 3, the reach rod 41 will move substantial y in a straight line due to the direction of the forces acting on'it. If necessary additional means may be rovided for causing it to move substantia y in a straight line.

By'movement ratio ofthe reach rod to the pedal, I `mean the rate of movement of the reach rod as compared to the rate of movement of the peda The construction shown in Figs. 1 and 3, wherel a cam is used, gives a relatively high constant movement ratio for the first third of the pedal travel, then an abrupt change which lower ratio remains substantiall constant for the remaining two-thirds of t e pedal travel.

In Fig. 2, where a link construction' is used, the movement ratio varies continually with no abrupt change, but decreases as the pedal movement ro resses, so that the reach rod moves uic y at first, and slowly and `powerfully in the latter part of its movement.

Having thus described my invention,'what l vfor causing actuation of the brake mechabetween said` nism and transmission means pedal and reach `rod comprising means whereby the movement 'ratio of the reach rod to the pedal decreases substantially as the pedaldmovement progresses, said last means comprising a lever pivoted to said reach rod and a pair of connections between the pedal and lever.

2. A brake construction comprising a pedal, a longitudinal reciprocable reach rod for causing actuation of the brake mechanism and transmission means between said pedal and reach rod comprising means whereby the movement ratio 'of the reach rod to the pedal decreases substantially as the pedal movement progresses, said lastl means comprising a lever ivoted to said reach rod and a link pivotaiiy connected at yone end to said lever and at the other end to said pedal, said pedal having a tion acting on said lever.

3. A brake construction comprising a pedal, a longitudinal reciprocable reach rod for causing actuation of the brake mechanism and transmission means between said pedal and reach rod comprisin means whereby themovement ratio of t e reach cam por- .rod to the pedal decreases substantially as 4. Brake-operating mechanism comprisl ing, in combination, a pedal, a brake applying connection, a lever rocked by depression of the pedal and operating the brake applying connection, and lever-engaging means moved by depression of the pedal for shifting the fulerum of the lever.

Brake-operating mechanism comprising,in combination, a pedal, a brake applying connection, a lever rocked by depression of the pedal and operating the brake applying connection, and lever-engaging means moved by depression of the pedal for shifting the fulcrnm of the lever lto vary the effective lever arm as the pedal is depressed to secure greater power near ythe end of the stroke of the pedal.

6. Brake-operating mechanism comprising, in combination, a brake-operating member, a pedal, a lever operating the brake-operating member, and two connections from the pedal to said lever, one constituting a shiftable fulcrum and the other rocking the lever about the fulcrum, the fulcrum being shifted automatically by its connection when the pedal is depressed to increase the leverage near the end of the stroke of the pedal.

7. Brake-operating mechanism comprising, in combination, a brake-operating meinber, a pedal, a lever operating the brakeoperating member, and two connections from the pedal to said lever, one constituting a shiftable fulcrum and the other being a link arranged to rock the lever about the fulcrum, the fulcrum being shifted automatically by its connection when the pedal is depressed to increase the leverage near the end of the stroke of the pedal.

In witness whereof, l have hereunto subscribed niy name.

ADIEL Y. DODGE. 

